Machine for manufacturing pouches of cohesionless material

ABSTRACT

A machine manufacturing pouches of a smokeless tobacco product, or other similarly cohesionless material, comprises a feed system ( 100 ) by which the tobacco is supplied to a conveyor ( 4 ) at a delivery station ( 5 ), from where it is transported by the conveyor ( 4 ) to a transfer station ( 6 ), also a system ( 102 ) operating at the transfer station ( 6 ) by which predetermined portions ( 7 ) of the product are directed from the conveyor ( 4 ) into at least one duct ( 16 ) linked to a form-fill-and-seal wrapping station ( 8 ) where the portions ( 7 ) are enclosed in a continuous succession ( 101 ) of pouches ( 2 ). The wrapping station ( 8 ) is equipped with ultrasonic welders.

This application is the National Phase of International ApplicationPCT/IB2008/000663 filed on Mar. 19, 2008 which designated the U.S. andthat International Application was published under PCT Article 21(2) inEnglish.

This application claims priority to Italian Patent ApplicationBO2007A000197 filed Mar. 20, 2007 and PCT/IB2008/000663 filed Mar. 19,2008, which applications are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a machine for manufacturing individualbags or sachets of cohesionless material, and in particular, pouches ofnasal snuff, or of moist snuff (also known as snus) for oral use.

Reference is made explicitly to tobacco in the course of the followingspecification, albeit no limitation in scope is implied, as thecohesionless material might consist similarly, for example, in powderedpharmaceutical or confectionery products treated with moisturizingagents.

BACKGROUND ART

The prior art embraces machines of the type in question, which comprisea dispensing disc rotatable intermittently about a vertical axis andfurnished with a ring of cavities, each containing a quantity or portionof tobacco that will correspond to the contents of a single pouch.

The portions are released into the single cavities at a filling stationfrom a hopper containing a supply of powdered tobacco en masse, treatedwith flavouring and moisturizing agents.

With the disc in rotation, the cavities are directed through a transferstation where the single portion of tobacco contained in each cavity isejected.

Installed at this same station are pneumatic ejection means comprising anozzle positioned above the dispensing disc. At each pause in themovement of the disc, a portion of tobacco is forced by the nozzle fromthe relative cavity into a duct, of which the mouth lies beneath thedisc and in alignment with the nozzle, and toward a wrapping stationwhere the single pouches are formed.

The wrapping station comprises a tubular element, placed at the outletof the duct and functioning as a mandrel over which to fashion a tubularenvelope, for example, of paper material or nonwoven fabric.

The material in question consists of a continuous web decoiled from aroll and fed in a direction parallel to the axis of the tubular element,which is wrapped progressively around the element and sealedlongitudinally.

Beyond the tubular element, the machine is equipped with transversesealing means of which the operation is intermittent and synchronizedwith the transfer of the tobacco portions, in such a way that eachsuccessive portion will be sealed in a relative segment of thecontinuous tubular envelope of wrapping material delimited by twoconsecutive transverse seals.

The successive tubular segments of wrapping material, formed as pouchescontaining respective portions of tobacco, are separated one from thenext through the action of cutting means positioned downstream of thetransverse sealing means.

Machines of the type in question present certain drawbacks.

In effect, such machines are not able to guarantee a completely smoothflow of the tobacco product through the connecting duct and the tubularelement.

The amount of tobacco deposited on the walls of the connecting duct andthe tubular element increases significantly, in particular, when themoisture content of the tobacco exceeds certain limits, jeopardizingcorrect operation of the machine.

In order to remove the tobacco accumulating internally of the connectingduct and of the tubular element, the machine must be shut down,whereupon these same parts have to be dismantled so that the tobaccodeposited on their inside surfaces can be removed by hand.

These operations are a source of high maintenance costs, and have theeffect of reducing production capacity.

The object of the present invention is to provide a machine formanufacturing single pouches of smokeless tobacco that will beunaffected by the drawbacks mentioned above in connection with machinesof the prior art, and able to guarantee a high production tempo whileavoiding the formation of tobacco deposits internally of theaforementioned connecting duct and tubular element.

DISCLOSURE OF THE INVENTION

The invention will now be described in detail, by way of example, withthe aid of the accompanying drawing,

FIG. 1, which shows a machine according to the present invention, viewedschematically and in a front elevation.

With reference to FIG. 1, numeral 1 denotes a machine for manufacturingpouches 2 containing a cohesionless material, in particular a smokelesstobacco product.

The machine 1 comprises a hopper 3 filled with the material in questionand constituting tobacco feed means 100, also conveying means 4rotatable between a delivery station 5 at which the cohesionless tobaccomaterial is taken up from the feed means, and a transfer station 6 atwhich successive portions 7 of tobacco are ejected.

The machine 1 further comprises a wrapping station 8 where the portions7 of tobacco removed from the transfer station 6 are taken up andenclosed in respective pouches 2.

The conveying means 4 are embodied as a drum 9 rotatable intermittentlyand anticlockwise, as viewed in the drawing, about a horizontal axis A.The drum 9 is interposed between a bottom end of the hopper 3, delimitedby two side walls 3 a and 3 b, and the aforementioned transfer station6.

The drum 9 presents a cylindrical wall, denoted 10, that includes a band11 of predetermined width rendered permeable to air by a plurality ofthrough holes 11 a.

The enclosure 12 delimited by the cylindrical wall 10 is divided by tworadial walls 12 a and 12 b into two sectors, denoted 13 and 14.

A first sector 13, located adjacent to the outlet of the hopper 3 andextending around to the transfer station 6, is connected to a source ofnegative pressure (not illustrated).

A second sector 14, positioned adjacent to and in alignment with thetransfer station 6, is angularly complementary to the first sector 13and connected to a first source of compressed air (not illustrated).

The second sector 14 provides the machine 1 with forcing means 102.

Also indicated are interconnecting means denoted 15, embodied as arectilinear duct 16, interposed between the transfer station 6 and thewrapping station 8.

The mouth of the duct 16 is in fluid communication with a second sourceof compressed air (not illustrated)

The wrapping station 8 comprises a tubular mandrel 17 positioned at theoutlet end of the rectilinear duct 16, around which a continuous web 18a of wrapping material is formed into tubular envelope 18.

The web 18 a of material is decoiled from a roll (not illustrated) andwrapped around the tubular mandrel 17, by degrees, through the agency ofsuitable folding means.

The edges of the web are sealed by welders 19 positioned next to thetubular mandrel 17, so as to close the tubular envelope 18longitudinally.

As illustrated in FIG. 1, the machine 1 also comprises sealing means 20located beyond the tubular mandrel 17, of which the function is to bondthe tubular envelope 18 transversely and thus form a continuoussuccession 101 of pouches 2, each containing a single portion 7 oftobacco.

Advantageously, the longitudinal welders 19 and the transverse sealingmeans 20 are of ultrasonic type.

More exactly, the longitudinal ultrasonic welders 19 are located inclose proximity to, and substantially in contact with the tubularmandrel 17.

Also forming part of the wrapping station 8 are aspirating means 21,located at the outlet end of the tubular mandrel 17 and able, given theporosity of the wrapping material, to create a draught internally of themandrel 17 such as will ease the passage of the tobacco along theselfsame mandrel.

The transverse sealing means 20 are followed downstream by a pair oftransport belts 22 looped around respective pairs of pulleys 22 a,serving to advance the continuous succession 101 of pouches 2 towardcutting means 23 by which the single pouches 2 of the succession 101 areseparated one from the next.

In operation, with the drum 9 set in rotation and exposed to theaspirating action of the negative pressure source, the air-permeableband 11 will gradually attract a continuous stream 24 of tobacco.

The continuous stream 24 advances as far as the transfer station 6,where a given length of the selfsame stream 24, corresponding inquantity to one portion 7, will be detached gradually from the drum by ajet of compressed air forced through the holes 11 a of the air-permeableband 11, and directed into the duct 16.

Forced along by the air jet, the portion 7 of tobacco passes along therectilinear connecting duct 16 and into the tubular mandrel 17, which isensheathed by the web 18 of wrapping material.

The portion 7 of tobacco is carried forward with the additional force ofthe air jet generated at the mouth of the rectilinear duct 16 by theaforementioned second source of compressed air.

The envelope 18 of paper is sealed lengthwise by the ultrasonic welders19, and crosswise, at the outlet end of the tubular mandrel 17, by thetransverse sealing means 20.

The operation of the transverse sealing means 20 is intermittent, andtimed to match the frequency at which successive portions 7 of tobaccoare fed into the transfer station 6, in such a way that each portion 7of tobacco will be enclosed between two consecutive transverse seals.

Thus, a continuous succession 101 of tobacco-filled pouches 2 willemerge, as aforementioned, joined one to the next by way of thetransverse seals.

At a given point downstream of the transverse sealing means 20, thesingle pouches 2 are separated one from the next by the cutting means23.

The elements of the design as described above are readily applicable toa twin track type of machine.

In this instance, the conveying means will consist in a drum with twoair-permeable bands, in such a way that two portions of tobacco can besupplied simultaneously to the transfer station, and each then directedinto a respective duct.

Self-evidently, the machine according to the present invention is ableto overcome the aforementioned drawbacks connected with the prior art,by virtue of the fact that the ultrasonic longitudinal welding meansserve not only to form the tubular envelope of wrapping material, butalso to generate a shaking action on the tubular mandrel internally ofwhich the tobacco advances, and thus prevent the accumulation ofdeposits on the inside wall of the mandrel.

Accordingly, the mandrel remains free of obstructions internally, andthere is no need for any stoppage of the machine to allow the removal oftobacco deposits manually from the inside wall.

1) A machine for manufacturing pouches (2) of cohesionless material, comprising: feed means (100) by which the material is supplied to conveying means (4) at a delivery station (5), from where the selfsame material is transported by the conveying means (4) to a transfer station (6); forcing means (102), operating at the transfer station (6), by which predetermined portions (7) of the material are directed from the conveying means (4) into at least one connecting duct (12) associated with a wrapping station (8) where the portions (7) are enclosed in a continuous succession of pouches (2); characterized in that the wrapping station (8) is equipped with ultrasonic welding means (19). 2) A machine as in claim 1, wherein the wrapping station (8) comprises a tubular mandrel (17) positioned at the outlet end of the connecting duct (16), around which a continuous web (18 a) of wrapping material is formed into tubular envelope (18), the welding means (19) serving to seal the tubular envelope (18) longitudinally and operating substantially in contact with the tubular mandrel (17) in such a way as to transmit vibrations at ultrasonic frequencies to the selfsame mandrel (17). 3) A machine as in claim 2, wherein the wrapping station (8) comprises ultrasonic sealing means (20) located downstream of the tubular mandrel (17), of which the function is to bond the tubular envelope (18) transversely and thus form a continuous succession (101) of pouches (2). 4) A machine as in claim 2, wherein the wrapping station (8) further comprises aspirating means (21) operating at the outlet end of the tubular mandrel (17). 